jQuery check if element exists

This question already has an answer here:

Check if element exists in jQuery [duplicate] 8 answers

---

从...开始

if (!jQuery('.fixit').length) return;

---

if ($('.fixit').length) {

     var el = jQuery('.fixit'),
           offset = el.offset(),
           elHeight = el.height(),
           scrollTop = jQuery(window).scrollTop()
           if (((offset.top + 400) < scrollTop - el.height())) {
               el.addClass('fixedElement');
           }

       if (scrollTop === 0) {
           el.removeClass('fixedElement');
       }

}

链接地址: http://www.djcxy.com/p/83692.html

上一篇: 如何检查jQuery的FIND结果

下一篇: jQuery检查元素是否存在